The evolution of mobile networks has driven service providers to develop increasingly complex and value-added network services. The next generation of mobile users will be able to connect to these network services through a variety of devices (e.g., mobile phones, laptop computers, Personal Digital Assistant (PDA), etc.) via multiple access networks (e.g., 802.11, Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM), cable, Digital Subscriber Line (DSL), etc). As the use of such varied device to access services via such access networks grows, it becomes important to ensure that these devices and networks work cooperatively together. For example, transfers (handoffs) of active communications sessions from one device to another and/or from one access network type to another will become increasingly desirable. Due to the increasing variety of protocols and message handling capabilities supported by different devices and networks, such transfers may present new problems. For example, some devices (e.g., cellular telephones, PDAs) will not be able to support the same data rate as a device with more processing capabilities (e.g., a laptop computer). As such, the tailoring of ongoing application sessions, for example active communication sessions between a service provider and a device, to accommodate the capabilities of the different devices/networks will become increasingly important.
User device capabilities do not need to be limited to an individual device. For example, while it is possible to perform many tasks on a single device, the availability of other devices can improve the services provided to a user. Therefore, as is well known, Personal Access Networks (PAN) have been developed that allow a user to cooperatively utilize a number of devices which are locally networked to support the user session. For example, a display device in an automobile may be part of a PAN having a cellular telephone with a broadband wireless internet connection. The information received via the internet connection may be displayed on the display device in the automobile. As such Personal Area Networks become increasingly popular, the capability to support transferring of an application session from a single device to distributing the same application session over several devices within a local network will become important.
Existing methods of handoffs have been used in transferring a data communication session between devices and/or networks. For example, well-known cellular hand-off technology and Mobile IP techniques function to maintain a communication session as devices change networks and/or obtain new IP addresses. Thus, communications are maintained transparently with no loss in data as a terminal changes access networks. However, while these techniques allow changes of networks, they do not support handoffs between devices. In another prior attempt, networks using Voice over IP (VoIP) protocols, such as the well-known Session Initiation Protocol (SIP), allow users to change terminals and networks while in a real-time communication session. However, these VoIP protocols typically simply transfer or redirect a call from one device/terminal to another based on the IP address of the terminal. There are provisions in these protocols to take into account device capabilities and configuration to modify the communication session content in a way such that it is tailored to a particular device. However, SIP is typically targeted for only real-time applications. In addition, SIP cannot handle distribution of an application to multiple devices.